Hex Viewer Plug-in
Use the Hex Viewer plug-in for comparing non-text data, or for examining control characters in text files. It displays two files side-by-side, each in the familiar hex layout of byte values followed by their ascii equivalent. Differences are highlighted in color, and a thumbnail view gives an overview of where differences exist.
If you right-click on a byte, the popup menu shows the decimal value of that byte, as well as multi-byte numbers beginning at that byte: